vertebrate

Any of a subphylum (Vertebrata) of chordates
having individual disks of bone or cartilage called vertebra surrounding or replacing the embryonic notochord ti form a jointed backbone that encloses the spinal column. Vertebrates
include:

A general body plan consisting of head, trunk, two pairs of appendages,
and post anal tail (though these structures are highly modified in many
vertebrates and sometimes absent).

Vertebrates have existed on Earth for more than 500 million years, from
the late Cambrian to the present day. The
first vertebrates lacked jaws, like the living hagfish and lampreys. Jawed
vertebrates appeared 100 million years later, in the Silurian.